-- Mathlib/Topology/EMetricSpace/Defs.lean
theorem PseudoEMetricSpace.ext {α : Type*} {m m' : PseudoEMetricSpace α}
    (h : m.toEDist = m'.toEDist) : m = m'

Proof state:
case mk
α : Type u_2
m' : PseudoEMetricSpace α
toEDist✝ : EDist α
edist_self✝ : ∀ (x : α), edist x x = 0
edist_comm✝ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U : UniformSpace α
hU : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
h : toEDist = toEDist
⊢ mk edist_self✝ edist_comm✝ edist_triangle✝ U hU = m'

Tactic:
rename EDist α => ed

Result:
case mk
α : Type u_2
m' : PseudoEMetricSpace α
ed : EDist α
edist_self✝ : ∀ (x : α), edist x x = 0
edist_comm✝ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U : UniformSpace α
hU : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
h : toEDist = toEDist
⊢ mk edist_self✝ edist_comm✝ edist_triangle✝ U hU = m'

Proof state:
case mk.mk
α : Type u_2
ed : EDist α
edist_self✝¹ : ∀ (x : α), edist x x = 0
edist_comm✝¹ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝¹ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U : UniformSpace α
hU : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
ed' : EDist α
edist_self✝ : ∀ (x : α), edist x x = 0
edist_comm✝ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U' : UniformSpace α
hU' : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
h : toEDist = toEDist
⊢ mk edist_self✝¹ edist_comm✝¹ edist_triangle✝¹ U hU = mk edist_self✝ edist_comm✝ edist_triangle✝ U' hU'

Tactic:
congr 1

Result:
case mk.mk.e_toUniformSpace
α : Type u_2
ed : EDist α
edist_self✝¹ : ∀ (x : α), edist x x = 0
edist_comm✝¹ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝¹ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U : UniformSpace α
hU : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
ed' : EDist α
edist_self✝ : ∀ (x : α), edist x x = 0
edist_comm✝ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U' : UniformSpace α
hU' : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
h : toEDist = toEDist
⊢ U = U'

Proof state:
α : Type u_2
m m' : PseudoEMetricSpace α
h : toEDist = toEDist
⊢ m = m'

Tactic:
obtain ⟨_, _, _, U, hU⟩ := m

Result:
case mk
α : Type u_2
m' : PseudoEMetricSpace α
toEDist✝ : EDist α
edist_self✝ : ∀ (x : α), edist x x = 0
edist_comm✝ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U : UniformSpace α
hU : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
h : toEDist = toEDist
⊢ mk edist_self✝ edist_comm✝ edist_triangle✝ U hU = m'

Proof state:
case mk.mk
α : Type u_2
ed : EDist α
edist_self✝¹ : ∀ (x : α), edist x x = 0
edist_comm✝¹ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝¹ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U : UniformSpace α
hU : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
toEDist✝ : EDist α
edist_self✝ : ∀ (x : α), edist x x = 0
edist_comm✝ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U' : UniformSpace α
hU' : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
h : toEDist = toEDist
⊢ mk edist_self✝¹ edist_comm✝¹ edist_triangle✝¹ U hU = mk edist_self✝ edist_comm✝ edist_triangle✝ U' hU'

Tactic:
rename EDist α => ed'

Result:
case mk.mk
α : Type u_2
ed : EDist α
edist_self✝¹ : ∀ (x : α), edist x x = 0
edist_comm✝¹ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝¹ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U : UniformSpace α
hU : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
ed' : EDist α
edist_self✝ : ∀ (x : α), edist x x = 0
edist_comm✝ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U' : UniformSpace α
hU' : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
h : toEDist = toEDist
⊢ mk edist_self✝¹ edist_comm✝¹ edist_triangle✝¹ U hU = mk edist_self✝ edist_comm✝ edist_triangle✝ U' hU'

Proof state:
case mk
α : Type u_2
m' : PseudoEMetricSpace α
ed : EDist α
edist_self✝ : ∀ (x : α), edist x x = 0
edist_comm✝ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U : UniformSpace α
hU : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
h : toEDist = toEDist
⊢ mk edist_self✝ edist_comm✝ edist_triangle✝ U hU = m'

Tactic:
obtain ⟨_, _, _, U', hU'⟩ := m'

Result:
case mk.mk
α : Type u_2
ed : EDist α
edist_self✝¹ : ∀ (x : α), edist x x = 0
edist_comm✝¹ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝¹ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U : UniformSpace α
hU : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
toEDist✝ : EDist α
edist_self✝ : ∀ (x : α), edist x x = 0
edist_comm✝ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U' : UniformSpace α
hU' : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
h : toEDist = toEDist
⊢ mk edist_self✝¹ edist_comm✝¹ edist_triangle✝¹ U hU = mk edist_self✝ edist_comm✝ edist_triangle✝ U' hU'

Proof state:
case mk.mk.e_toUniformSpace
α : Type u_2
ed : EDist α
edist_self✝¹ : ∀ (x : α), edist x x = 0
edist_comm✝¹ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝¹ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U : UniformSpace α
hU : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
ed' : EDist α
edist_self✝ : ∀ (x : α), edist x x = 0
edist_comm✝ : ∀ (x y : α), edist x y = edist y x
edist_triangle✝ : ∀ (x y z : α), edist x z ≤ edist x y + edist y z
U' : UniformSpace α
hU' : 𝓤 α = ⨅ ε, ⨅ (_ : ε > 0), 𝓟 {p | edist p.1 p.2 < ε}
h : toEDist = toEDist
⊢ U = U'

Tactic:
exact UniformSpace.ext (((show ed = ed' from h) ▸ hU).trans hU'.symm)

Result:
no goals